Hydrogen gas detection device

Abstract

In a hydrogen gas detection device, light emitted from a light source is irradiated onto a hydrogen sensor whose reflectance (optical reflectance) varies upon contact with hydrogen gas, and the light transmitted through the hydrogen sensor or reflected by a reflective film of the hydrogen sensor is received by an optical sensor. On the basis of the signal output from the optical sensor and indicative of the amount of light received, the hydrogen gas detection device detects leakage of hydrogen gas.

1. A hydrogen gas detection device comprising:
 a hydrogen sensor including a substrate capable of transmitting light therethrough, 
 a first reflective film formed on one surface of the substrate, 
 a second reflective film formed on an opposite surface of the substrate, 
 an optical input port for admitting light to one end of the substrate, and 
 an optical output port for receiving the light that arrives at an opposite end of the substrate after being input from the optical input port and then reflected alternately by the first and second reflective films, and for allowing the received light to be output to outside of the substrate, wherein reflectance of either one or both of the first and second reflective films varies upon contact with hydrogen gas; 
 a light source for inputting the light to the optical input port; and 
 an optical sensor for receiving the light output from the optical output port and outputting a detection signal; 
 wherein the first and/or second reflective film of which the reflectance varies upon contact with hydrogen gas includes: 
 a thin-film layer formed on the corresponding surface of the substrate; and 
 a catalyst layer formed on a surface of the thin-film layer, the catalyst layer hydrogenating the thin-film layer upon contact with hydrogen gas to vary reflectance of the thin-film layer. 
 
     
     
       2. A hydrogen gas detection device comprising:
 a plurality of hydrogen sensors each including a substrate capable of transmitting light therethrough, a first reflective film formed on one surface of the substrate, a second reflective film formed on an opposite surface of the substrate, an optical input port for admitting light to one end of the substrate, and an optical output port for receiving the light that arrives at an opposite end of the substrate after being input from the optical input port and then reflected alternately by the first and second reflective films, and for allowing the received light to be output to outside of the substrate, wherein reflectance of either one or both of the first and second reflective films varies upon contact with hydrogen gas; 
 optical transmission means for cascade-connecting the hydrogen sensors to form an optical circuit; 
 a light source for inputting the light to the optical input port of that one of the cascade-connected hydrogen sensors which is situated at input end of the optical circuit; and 
 an optical sensor for receiving the light output from the optical output port of that one of the cascade-connected hydrogen sensors which is situated at an output end of the optical circuit, and for outputting a detection signal. 
 
     
     
       3. The hydrogen gas detection device according to  claim 2 ,
 wherein the first and/or second reflective film of which the reflectance varies upon contact with hydrogen gas includes: 
 a thin-film layer formed on the corresponding surface of the substrate; and 
 a catalyst layer formed on a surface of the thin-film layer, the catalyst layer hydrogenating the thin-film layer upon contact with hydrogen gas to vary reflectance of the thin-film layer.